Oroville Spillway Incident Resource Page

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On March 3, the flood control spillway flows remain at 0 cubic feet per second (cfs). Inflows are approximately 15,000 to 20,000 cfs, which has resulted in the lake rising from 845.6 feet to 848.3 feet elevation in the last 24 hours. Contractors continue to remove sediment and debris below the spillway. Approximately 168,000 cubic yards of material have been removed from the debris pile to date.  (More info below) 

 


 


​​Incident Description

On Feb. 27, the Department of Water Resources (DWR) gradually ramped down outflows from the Oroville Reservoir. Flows from the flood control spillway were reduced from 50,000 cubic feet per second throughout the day and eventually reached zero in the afternoon.

On Feb. 24, the Department of Water Resources (DWR) reduced the outflow from the Oroville Dam flood control spillway to 50,000 cubic feet per second, in an effort to support debris removal from the diversion pool, located near the spillway. This rate of flow remains consistent with DWR’s established plan to continually manage lake levels, water flow, and support construction activities. Lake levels have decreased to 849 feet, 52 feet below the maximum level of the reservoir. Outflows are once again exceeding inflows.

On Feb. 23, the Department of Water Resources continued to discharge 60,000 cubic feet per second (cfs) of water from the Oroville Dam flood control spillway. Lake levels decreased to 851 feet, 50 feet below the maximum level of the reservoir. Outflows are once again exceeding inflows

On Feb. 22, the Department of Water Resources continued to discharge 60,000 cubic feet per second (cfs) of water from the Oroville Dam flood control spillway. Lake levels rose slightly to 853 feet, 48 feet below the maximum level of the reservoir. Inflows exceeded outflows during the current storm system but are forecasted to be below outflows in the next 24 hours

On Feb. 21, the Department of Water Resources (DWR) maintained an outflow, from the Oroville Dam flood control spillway, at 60,000 cubic feet per second (cfs) throughout the day. The rate of flow was consistent with DWR’s established plan objectives to continually manage lake levels, water flow, and support construction activities.

On Feb. 20, the Department of Water Resources increased outflow from the Oroville Dam flood control spillway yesterday, from 55,000 cubic feet per second to 60,000 cfs, in anticipation of the expected increase in inflows. This proactive measure is typical of normal flood control operations and is in anticipation of forecasted weather conditions. The increase is temporary and is expected to better balance water flow in and out of the reservoir.

On Feb. 19, flows were reduced to 55,000 cubic feet per second (cfs) and continued to outpace the inflow encountered. The reduction in flow allowed assessment teams to view debris buildup and dredge debris piles below the flood control spillway. Lake elevations continued trending downward and had fallen to 854 feet.

On Feb. 18, the Department of Water Resources initiated the reduction of outflow from the Oroville Dam flood control spillway, incrementally from 70,000 cubic feet per second to 55,000 cfs, in an effort to support debris removal from the diversion pool, located near the spillway. Once flows have been reduced, DWR will hold, monitor, and evaluate whether to reduce outflows further to support construction efforts.

On Feb. 17, construction crews for the Department of Water Resources continue to repair erosion below the emergency spillway. Rock, aggregate and cement slurry are being used to repair and backfill the affected areas. As of 8 a.m., water flow from the flood control spillway was 80,000 cubic feet per second. This reduced outflow is allowing debris removal from the diversion pool, below the spillway. The level of the reservoir has been reduced by 40 feet to accommodate inflow from current and forecasted inclement weather and is not expected to exceed anticipated outflows.

On Feb. 16, the California Department of Water Resources began reducing outflow from the Oroville Dam flood control spillway to support the removal of debris from the diversion pool located near the spillway. Removal of debris from the diversion pool further protects, safeguard​​s, and provides for the eventual reoperation of the Hyatt power plant. As of 8 a.m., the lake level sat at 32 feet below the emergency spillway height and 100,000 cubic feet per second (cfs) continues to flow through the flood control spillway.

On Feb. 15, the Department of Water Resources continues to reinforce the emergency spillway. More than 125 construction crews are working around the clock, and are placing 1,200 tons of material on the spillway per hour, using helicopters and heavy construction equipment.

On Feb. 14, President Trump approved federal emergency aid to be made available to the State of California to supplement State, tribal, and local response efforts due to the emergency conditions resulting from the potential failure of the emergency spillway at Lake Oroville Dam. Meanwhile, the Butte County Sheriff’s Department reduced the evacuation order to a warning, allowing residents and businesses to return to their normal activity. The California Department of Water Resources maintained a release of 100,000 cubic feet per second (cfs) and inflow continued to drop to 19,000 cfs. 

On Feb. 13, with no water flowing over the emergency spillway, the California Department of Water Resources continued to release water flow at 100,000 cubic feet per second (cfs). The evacuation order was still in effect. 

On Feb. 12, the Lake Oroville Dam emergency spillway structure suffered potentially catastrophic damage as a result of erosion secondary to water flow. The California Department of Water Resources increased exhaust water flow from the Gated Spillway to 100,000 cubic feet per second in an attempt to decrease Lake Oroville water levels. In response, the California Governor’s Office of Emergency Services activated the State Operations Center in Sacramento in support of the Oroville Dam emergency spillway incident. Immediate evacuations were ordered for counties and cities near Lake Oroville, and Governor Brown issued state of emergency to help mobilize disaster response resources and support the local evacuations.​

 

Overview

​​​​On Feb. 11, a relatively light flow of water that began washing into Lake Oroville’s emergency spillway was expected to continue flowing for the next few days. The lake exceeded the elevation of 901 feet above sea level shortly after 8 a.m., at which point water slowly began to flow over the concrete weir of the auxiliary spillway, down a hillside, and into the Feather River.  On Feb. 9, the California Department of Water Resources personnel and a host of collaborating agencies continued to monitor Lake Oroville spillway flows through the night. As expected, the overnight flow rate of 20,000 cubic feet per second (cfs) caused additional lower spillway erosion. Spillway flow was stopped again for a few hours to allow engineers to evaluate the integrity of the structure. On Feb. 8, to help determine an appropriate level of flow down the damaged spillway at Oroville Dam, the California Department of Water Resources released up to 20,000 cubic feet per second (cfs), then ramped down the flows to assess any further damage to the eroded spillway.  ​On Feb. 7, the California Department of Water Resources temporarily suspended flows from the Oroville Dam spillway to investigate concrete erosion on the bottom half of the spillway.

 

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For current Lake Oroville storage conditions, click H​E​RE​.​ 


Go HERE to get the latest information on the Oroville Spillway Incident.

2016 Oroville Dam Inundation Map

Most dam owners are required to prepare inundation maps as part of the dam permitting process. These maps are prepared by civil engineers on behalf of dam owners, as required under California law. State law requires dam owners to submit inundation maps for approval by Cal OES. Inundation maps are developed from the best available information using reasonable assumptions and standardized methods. The maps are an approximation of the maximum water flow resulting from a complete dam failure. The maps portray a catastrophic failure of the dam, as opposed to the failure a critical appurtenant structure, such as a spillway. This map represents a worst-case scenario contemplating a complete failure of the Oroville Dam. Depending upon actual circumstances, appropriate alert and evacuation areas could be more or less extensive than the simulated zones shown on the maps.

Inundation Map for Oroville Dam 2016

​Shelters

There are currenty no shelters or evacuation centers open at this time.

 

 

Access and Fu​​nctional Needs

California Foundation for Independent Living Centers ​has set up an evacuation and shelter helpline for people with disabilities and seniors that need to evacuate: (843) 817-2651. If you need tra​​nsp​​ortation or assistance to evacuate or accessing a shelter, you can contact the Emergency Disability Access Line 24 Hours a day. ​​​​​

​Transportation​

Caltrans QuickMap​​​​​

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The Caltrans QuickMap web page presents several types of real-time traffic inf​ormation layered on a Google Map. The information includes traffic speed, lane and road closures due to construction and maintenance activities, incident reports, Changeable Message Sign (CMS) content, camera snapshots, and active chain control requirements.​​

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​Donations and Volunteering

How Can You Help? 

If you would like to donate, cash donations are preferred because they reduce the amount of labor and the expense of sorting, packing, transporting and distributing donated goods. Relief agencies can use cash to meet survivors’ specific needs more quickly while also supporting local economic recovery. For additional information and easy-to-use tips on avoiding charity scams following a disaster, please visit the California Office of the Attorney General Charities web site​.​

​Cooperating Agencies

 

 

 

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